1. Field of the Invention
This invention relates to the atomization of liquids and more particularly it concerns novel methods and apparatus for supplying liquid to be atomized to a surface of an orifice plate which, upon vibration, atomizes the liquid and ejects minute droplets of the liquid from its opposite surface.
2. Description of the Related Art
Atomizers of the type to which the present invention relates use a vibration orifice plate or membrane to atomize liquid which is brought to one side of the plate by a pliant wick which presses against the plate. An example of such an atomizer is shown in U.S. Pat. No. 6,450,419.
Atomizing devices that use wicks or conduits of various types to deliver liquids to a vibratory atomizing element are disclosed in U.S. Pat. Nos. 6,467,476, 6,085,740, 5,529,055, 4,790,479, 4,753,579, 4,334,531 and U.S. Pat. No. 4,301,093 and published European Patent Application EP 0 897 755 A2. U.S. Pat. Nos. 4,582,654 and 4,474,326 describe the use of tubes or needles to deliver a liquid to be atomized. U.S. Pat. Nos. 5,863,196 and 5,124,200 describe wicks.
Our invention solves a problem which occurs when a solid, dimensionally stable wick is used to convey the liquid to be atomized to the orifice plate. An example of an atomizing device which uses a solid, dimensionally stable wick is shown and described in U.S. patent application Ser. No. 10/154,509, filed May 24, 2002, assigned to the assignee of this invention and incorporated herein by reference. Such wicks are generally made of plastic and contain interstices or capillary passages, which extend therethrough from one end to the other to draw liquids up through the wick from one end of the wick to its other end. It has been found that when the wick of a replacement reservoir is positioned against an orifice plate that is still wet from the wick of a previous reservoir, it is often difficult to restart the atomizing operation. It may take hours or even days for the atomizing operation to restart, which adversely affects the use of the atomizer.
Accordingly, we found a need in the art for an atomization device that is “self priming,” meaning that the wick included in the atomization device reliably and instantaneously delivers fluid to a piezoelectric pump.